This invention relates to a rock wall closure detection apparatus for detecting and signalling movement of one rock wall in an excavation relative to another, to forewarn workers in the excavation of the possibility of rock fall and, more particularly, to an apparatus that can be re-deployable.
Most apparatus that are adapted to provide an indication of relative movement in rock walls are permanently or semi-permanently fixed in position, typically within a rock hole formed in a particular rock wall.
Such apparatus are not easily re-usable, or capable of easy dis-assembly and re-assembly in another location.
Moreover, there are circumstances when the integrity of the hanging wall is so compromised that it is unsafe to proceed into the space below the hanging wall to install such apparatus.
The present invention, at least partially, addresses the aforementioned problem.